The present invention relates generally to systems and methods of detecting biological and/or chemical agents, and more particularly, a system and method that uses luminescent piezoelectric to detect these biological and chemical agents.
Biological and chemical element detection are currently considered to be among the highest priorities to scientific, personal and medical, as well as national security. A significant concern is the inability to even detect the presence or nature of the various chemical or biological agents in a timely manner. This inability seriously impairs the implementation of appropriate responses. Existing detection methods either depend upon on-site sample collection, with the undesirable possibility of exposing or infecting personnel in the case of virile environments, and subsequent, time-consuming/sensitive laboratory analysis; or the use of (quasi-) real-time remote spectroscopic analysis of the surrounding and/or immediate environment which may or may not be directly coupled to or preserving of the element(s) in question. On-site sample collection is difficult, time consuming and expensive. Additionally, this method suffers from the need for large numbers of samples, especially for thinly dispersed (virile) biological agents and/or chemical elements or toxins, and a number of fully equipped virilogical/histrological laboratories near the immediate vicinity for a truly accurate analysis. Even if such facilities are readily available, some agents require days to weeks for unambiguous identification-an unsatisfactory time-frame much too long for many medical/personal and scientific operations. The second approach of using remote spectroscopic (optical) analysis may have an advantage of (quasi-) real-time identification but only works when the agents in question are sufficiently concentrated to yield a detectable signal. This technique is also a high cost solution which will not be affordable for very many large areas, multi-unit operations.
It would be desirable to have a system that allows the possibility of a real-time biological/chemical sensor. Furthermore, the need exists for such a sensor that is both small and inexpensive. This would allow distribution to only personnel to be alerted on an individual bases to possible exposures(s) and reactions, and to aid subsequent medical personnel in their post-exposure treatment strategy and/or status monitorings.
This latter need addresses not only the interests of the scientific and laboratory communities, but also immediate needs within the medical and biomedical arenas in the areas of personal prognostic health monitoring.
The present invention provides a biological and chemical agent detection system and method that substantially eliminates or reduces disadvantages and problems associated with previously developed systems and methods.
More specifically, the present invention provides a system for detecting chemical and biological agents using luminescent piezoelectrics.
The present invention includes a free-standing thin film EL phosphor onto which a biological and/or chemical active surface layer has been deposited. The EL film is electronically or mechanically excited to, or near resonance, and the edge emitted light intensity is measured. Upon exposure to the appropriate agent, the surface layer either increases in mass, decreases in mass, changes its surface tension, changes its viscosity, etc., thereby changing the resonators response to the driving frequency. This will either be detected as a change in the emitted light intensity or a shift in the driving frequency to achieve the same light intensity thereby indicating the presence and/or concentration of the agent.
Other important embodiments examine changes in the surface layer""s optical coupling to the resonator (e.g., through gratings or other optical structures fabricated on the free-standing film surface) thereby increasing/decreasing the amount of light scattered out of the flat surface of the thin film waveguide and/or providing the spectral content/signature of the emitted light/specimen.
Other designs may include the use of an atomic stylus or tip configuration as used in atomic force microscopes to enhance/amplify the sensitivity of the sensor by an order of magnitude or more.
Another embodiment may integrate micro-sensors which can be integrated directly onto the edges or surfaces where the signal or light emission occurs in order to provide tremendous increases in the sensing capability as compared to a strictly visual sensing.
In yet another embodiment, combinations of nanometer-micron thick phosphor and/or film stacks (including porous structures/materials) may be used to provide a color discriminator between an uncontaminated and contaminated condition (e.g. green emission implies safe, but red emission implies danger).
The present invention provides an important technical advantage in that the use of porous materials such as gels or phosphors as the xe2x80x9cfilmxe2x80x9d structure serves as the elemental capturing mechanism. Porous materials (gels, phosphors, etc.) can be added either as a discrete capturing medium (i.e., xe2x80x9cdeposited filmxe2x80x9d) or fabricated as an integral (i.e., integrated) part of the free-standing resonant structure. Micro-optical structures such as spectroscopic gratings can be fabricated or etched into the porous materials themselves using ordinary processing techniques thereby resulting in a truly integrated structure with a tremendous reduction in cost and increase in performance and sensitivity (noise reduction in sampling/identification) due to the porous action as a micro-capillary device (elemental selectivity).
Yet another innovation provided by the present invention is the ability to heat the film/standing structure, which can be easily and/or inherently implemented in order to xe2x80x9cpurgexe2x80x9d the structure on a repeated and controlled basis thereby allowing for repeated/scheduled usage and the generation of an inherently stable baseline for operation.